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Breast Cancer

Breast Cancer Disease Information

Genentech BioOncology is dedicated to advancing the science of breast cancer therapy through comprehensive research programs and education. Breast cancer originates in breast tissue and arises from the ductal tissue of the breast and, less commonly, the lobular tissue.¹ There are several forms of breast cancer based, in part, on cellular and genetic characteristics.²

Types of Breast Cancer

HER2-Positive

Overabundance of the HER2 protein classifies the breast cancer as HER2-positive and causes breast cancer cells to multiply, spread more rapidly, and survive longer than other breast cancers³

Hormone Receptor-Positive

Breast cancer cells that express hormone receptors for estrogen (ER) and/or progesterone (PR) are dependent on the signaling of those receptors²

Triple Negative

Some women have a more difficult-to-treat form of breast cancer known as "triple-negative," which means they test negative for 3 main receptors (HER2, ER, and PR)²

Each form of breast cancer has a different prognosis. The American Society of Clinical Oncology recommends that all women diagnosed with breast cancer have tumor marker tests, which can help identify which type of breast cancer a patient has and help determine the best treatment options.⁴

Breast Cancer Demographic Statistics

Breast cancer is the second most commonly diagnosed cancer and the second leading cause of cancer deaths among women in the United States⁵
In 2010, more than 207,090 American women were diagnosed and nearly 40,000 died of breast cancer⁵
One in 4 women has HER2-positive breast cancer, a more aggressive type associated with a poorer prognosis³

Breast Cancer Epidemiology

Family history of breast cancer, or personal history of breast abnormalities, early age at first menstrual period, obesity, and physical inactivity can contribute to development of breast cancer⁵
- Inheritance of mutations in specific genes, such as BRCA1 and BRCA2 contributes to the relative risk of developing breast cancer⁵
African American women have an increased risk of developing and dying from breast cancer⁶
Prognosis of 5-year survival varies according to different characteristics⁵
- Only 23% of women with distant metastatic disease will live for 5 years⁵
- Women with HER2+ disease have a 5-year survival rate of 68%⁷
- 94% of women with HR+ disease can expect to live for 5 years²
- Women with triple-negative disease have a survival prognosis of 81% for 5 years²

Breast cancer is often detected early through the use of several exams, including self-exams and mammography exams.⁵ Additionally, there are biomarkers to predict risk for developing breast cancer that can contribute to early detection.⁴ However, there do remain less common symptoms including changes to the breast or nipple such as thickening, swelling, tenderness, skin irritation, redness, and scaliness that can potentially be misdiagnosed.⁵